A scanning probe microscope (SPM), which is a typical surface analyzer, is a device for scanning the surface of a sample with a micro-sized probe and detecting a force resulting from the interaction between the surface and the probe. This device is capable of collecting, on the same area of a sample, not only information on the altitude (surface height or surface shape) but also two-dimensional distribution data of various kinds of physical quantities, such as phase, electric current, viscoelasticity, magnetic force, surface potential or electrostatic force. In normal conventionally used SPMs, two-dimensional distribution data of the physical quantities measured on a predetermined area of a sample are processed into a two or three-dimensional image including additional information, such as color information, and displayed on the display screen of a monitor.
In SPMs, a kind of information that cannot be obtained from a distribution image of a certain kind of physical quantity may possibly be derived from a distribution image of another kind of physical quantity. Therefore, observers often desire to simultaneously refer to image information of two or more kinds of physical quantities, such as an altitude image and a phase image or a surface potential image and an electric current image. To satisfy such a demand, in an SPM described in Patent Document 1, a three-dimensional image created from a two-dimensional distribution data of one kind of physical quantity is displayed, and color information showing a two-dimensional distribution of another kind of physical quantity is mapped onto the three-dimensional image so that the correspondence relationship between the distributions of the two different physical quantities can be easily recognized on that image.
The display method described in Patent Document 1 enables users to roughly grasp the relationship of the two-dimensional distributions of different kinds of physical quantities within a predetermined measurement area on a sample. However, with this method, it is difficult to make detailed, quantitative determination about the relationship between the aforementioned physical quantities within a predetermined area of the sample surface. It is also difficult to accurately compare a plurality of characteristic values at a specific position on the sample. Naturally, even if a conventional SPM is used, it is possible to extract necessary characteristic values from the collected two-dimensional data of the physical quantities concerned and perform the aforementioned quantitative determination or comparison. However, such a task is complex as well as time-consuming.